From 0160953d8eec75c3c55562158c46442ff1fd410b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Fri, 18 Sep 2026 13:46:40 +0200 Subject: [PATCH] eth: fbnic: Avoid rounding zero ring sizes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit roundup_pow_of_two() is undefined for zero. ethtool permits a zero ring size to reach the driver, where the minimum-size check should reject it. Leave zero unchanged while rounding nonzero ring sizes. The minimum-size check then rejects zero deterministically without changing the established behavior for other values. Fixes: 6cbf18a05c06 ("eth: fbnic: support ring size configuration") Reported-by: Sashiko Link: https://lore.kernel.org/netdev/178971206933.22033.236948278674126701@kernel.org/ Suggested-by: Alexander Duyck Signed-off-by: Björn Töpel Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260918114641.1281172-1-bjorn@kernel.org Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c index 423f179c9d47..76e9a545bb16 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c @@ -313,6 +313,11 @@ fbnic_get_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, kernel_ring->hds_thresh = fbn->hds_thresh; } +static u32 fbnic_ring_size_pow2(u32 size) +{ + return size ? roundup_pow_of_two(size) : 0; +} + static void fbnic_set_rings(struct fbnic_net *fbn, struct ethtool_ringparam *ring, struct kernel_ethtool_ringparam *kernel_ring) @@ -334,10 +339,10 @@ fbnic_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring, struct fbnic_net *clone; int err; - ring->rx_pending = roundup_pow_of_two(ring->rx_pending); - ring->rx_mini_pending = roundup_pow_of_two(ring->rx_mini_pending); - ring->rx_jumbo_pending = roundup_pow_of_two(ring->rx_jumbo_pending); - ring->tx_pending = roundup_pow_of_two(ring->tx_pending); + ring->rx_pending = fbnic_ring_size_pow2(ring->rx_pending); + ring->rx_mini_pending = fbnic_ring_size_pow2(ring->rx_mini_pending); + ring->rx_jumbo_pending = fbnic_ring_size_pow2(ring->rx_jumbo_pending); + ring->tx_pending = fbnic_ring_size_pow2(ring->tx_pending); /* These are absolute minimums allowing the device and driver to operate * but not necessarily guarantee reasonable performance. Settings below